Different imaging methods are used for the three-dimensional representation of individual objects, such as individual body regions for example. One possible method is cone-beam volume tomography, with which individual, two-dimensional X-ray projections of the body region to be imaged are recorded from different directions and a computation of a three-dimensional representation is subsequently effected. An X-ray source and an X-ray detector move around the object to be imaged, for picture recording. A picture recording path of the X-ray source and the X-ray detector around the object to be imaged, for example a patient, and which is hereby applied, essentially determines the achievable, three-dimensional picture quality of cone-beam volume tomography.
A so-called completeness condition was formulated by Heang K. Tuy (H. Tuy, “An inversion formula for cone-beam reconstruction”, SIAM Journal of Applied Mathematics vol. 43, no. 3, pp. 546-552, 1983.), for an exact reconstruction of a volume region. This states that a volume can be reconstructed in an exact manner if all planes which run through the volume also intersect the picture recording path or movement path of the X-ray source at least once. Such a movement path however is difficult to implement, above all with an intra-operative application of cone-beam volume tomography in the operating theatre. In this case, a guarantee of sterility and a free access to the patient are necessary, apart from a high three-dimensional picture quality, i.e. the patient, as the object to imaged, should not be completely enclosed by a device which is used for imaging or by the picture recording path.
Apparatus known from the state of the art use a circular movement of the X-ray detector and of the X-ray source around the patient with an additional linear forwards movement (so that e.g. a spiral path results) or with an additional inclination. Such a device is e.g. known from the patent document U.S. Pat. No. 6,504,892 B1. A further possibility is to provide a simple circular path or orbit around the patient, with which the patient, although not being completely enclosed, the reconstruction of the scanned volume exclusively in a central plane is however complete. The volume outside this central plane cannot be reconstructed in an exact manner. Further solution possibilities comprise saddle-like movement paths which are also called sweep/wobble trajectories, or also the use of several individual orbits of the X-ray source about the target region, e.g. two circular paths running parallel to one another.